An indispensable manual for everyday github commands.

1. STASH

git stash
Lets you save the current working directory (un-committed files) safely , to view later.
Please note this does not save your un-tracked files.

1.1 Read what’s in a stash without applying
git stash show -p stash@{n}
where n is the index of the stashed change

1.2 Name Your Stash
git stash save "guacamole sauce WIP"

1.3 Apply a Named Stash
git stash apply stash^{/guacamo}
this will match all stashes starting with guacamo

1.4 Remove stash from the stash stack and apply
git stash pop stash@{n}
where n is the index of the stashed change

1.5 Delete a named stash
git stash drop - drops the first stash in the stash stack
git stash drop stash@{n} - drops the stash n from the stash stack

1.6 See stash list
git stash list

2. Revert a commit

git reset --hard HEAD~1

3. Pulling from someone else’s repo

git remote add <name_for_the_coworker> git://path/to/coworkers/repo.git
git fetch <name_for_the_coworker_given_above>

4. Squashing x commits together

git rebase -i HEAD~x - where x is the number of commits you want to squash together

The above command will open an interactive terminal in front which would look something like this:
pick f29001f a
pick 0ce2110 b
pick 6a3add5 c
pick d24c5a4 d

Now change pick to squash for each of the commit that you need to squash.
Next it will ask you to edit/change the commit message for the squash commit, which will be pre-populated with commit messages of the x commits you are trying to squash together.

References -
StackOverflow, StackOverflow, StackOverflow